Bumped version to 0.10.1

Fix roles during renegociation

CMakeLists.txt

@@ -1,6 +1,6 @@
 cmake_minimum_required(VERSION 3.7)
 project(libdatachannel
-	VERSION 0.10.0
+	VERSION 0.10.1
 	LANGUAGES CXX)
 set(PROJECT_DESCRIPTION "WebRTC Data Channels Library")
 
@@ -115,17 +115,15 @@ set(CMAKE_POLICY_DEFAULT_CMP0048 NEW)
 add_subdirectory(deps/plog)
 
 option(sctp_build_programs 0)
+option(sctp_build_shared_lib 0)
 add_subdirectory(deps/usrsctp EXCLUDE_FROM_ALL)
 if (MSYS OR MINGW)
 	target_compile_definitions(usrsctp PUBLIC -DSCTP_STDINT_INCLUDE=<stdint.h>)
-	target_compile_definitions(usrsctp-static PUBLIC -DSCTP_STDINT_INCLUDE=<stdint.h>)
 endif()
 if (CMAKE_CXX_COMPILER_ID MATCHES "GNU")
     target_compile_options(usrsctp PRIVATE -Wno-error=format-truncation)
-	target_compile_options(usrsctp-static PRIVATE -Wno-error=format-truncation)
 endif()
 add_library(Usrsctp::Usrsctp ALIAS usrsctp)
-add_library(Usrsctp::UsrsctpStatic ALIAS usrsctp-static)
 
 if (NO_WEBSOCKET)
 	add_library(datachannel SHARED
@@ -156,13 +154,13 @@ target_include_directories(datachannel PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/includ
 target_include_directories(datachannel PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include/rtc)
 target_include_directories(datachannel PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src)
 target_link_libraries(datachannel PUBLIC Threads::Threads plog::plog)
-target_link_libraries(datachannel PRIVATE Usrsctp::UsrsctpStatic)
+target_link_libraries(datachannel PRIVATE Usrsctp::Usrsctp)
 
 target_include_directories(datachannel-static PUBLIC ${CMAKE_CURRENT_SOURCE_DIR}/include)
 target_include_directories(datachannel-static PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include/rtc)
 target_include_directories(datachannel-static PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/src)
 target_link_libraries(datachannel-static PUBLIC Threads::Threads plog::plog)
-target_link_libraries(datachannel-static PRIVATE Usrsctp::UsrsctpStatic)
+target_link_libraries(datachannel-static PRIVATE Usrsctp::Usrsctp)
 
 if(WIN32)
 	target_link_libraries(datachannel PRIVATE ws2_32) # winsock2

include/rtc/include.hpp

@@ -102,12 +102,12 @@ private:
 	std::function<void()> function;
 };
 
-template <typename... P> class synchronized_callback {
+template <typename... Args> class synchronized_callback {
 public:
 	synchronized_callback() = default;
 	synchronized_callback(synchronized_callback &&cb) { *this = std::move(cb); }
 	synchronized_callback(const synchronized_callback &cb) { *this = cb; }
-	synchronized_callback(std::function<void(P...)> func) { *this = std::move(func); }
+	synchronized_callback(std::function<void(Args...)> func) { *this = std::move(func); }
 	~synchronized_callback() { *this = nullptr; }
 
 	synchronized_callback &operator=(synchronized_callback &&cb) {
@@ -123,16 +123,16 @@ public:
 		return *this;
 	}
 
-	synchronized_callback &operator=(std::function<void(P...)> func) {
+	synchronized_callback &operator=(std::function<void(Args...)> func) {
 		std::lock_guard lock(mutex);
 		callback = std::move(func);
 		return *this;
 	}
 
-	void operator()(P... args) const {
+	void operator()(Args... args) const {
 		std::lock_guard lock(mutex);
 		if (callback)
-			callback(args...);
+			callback(std::move(args)...);
 	}
 
 	operator bool() const {
@@ -140,8 +140,12 @@ public:
 		return callback ? true : false;
 	}
 
+	std::function<void(Args...)> wrap() const {
+		return [this](Args... args) { (*this)(std::move(args)...); };
+	}
+
 private:
-	std::function<void(P...)> callback;
+	std::function<void(Args...)> callback;
 	mutable std::recursive_mutex mutex;
 };
 } // namespace rtc

include/rtc/peerconnection.hpp

@@ -129,7 +129,7 @@ public:
 	void onTrack(std::function<void(std::shared_ptr<Track> track)> callback);
 
 private:
-	std::shared_ptr<IceTransport> initIceTransport(Description::Role role);
+	std::shared_ptr<IceTransport> initIceTransport();
 	std::shared_ptr<DtlsTransport> initDtlsTransport();
 	std::shared_ptr<SctpTransport> initSctpTransport();
 	void closeTransports();

include/rtc/rtp.hpp

@@ -57,6 +57,7 @@ public:
 
 	inline uint8_t version() const { return _first >> 6; }
 	inline bool padding() const { return (_first >> 5) & 0x01; }
+	inline bool extension() const { return (_first >> 4) & 0x01; }
 	inline uint8_t csrcCount() const { return _first & 0x0F; }
 	inline uint8_t marker() const { return _payloadType & 0b10000000; }
 	inline uint8_t payloadType() const { return _payloadType & 0b01111111; }
@@ -77,6 +78,17 @@ public:
 	inline void setSsrc(uint32_t ssrc) { _ssrc = htonl(ssrc); }
 
 	void setTimestamp(uint32_t i) { _timestamp = htonl(i); }
+
+	void log() {
+		PLOG_VERBOSE  << "RTP V: " << (int) version()
+		            << " P: " << (padding() ? "P" : " ")
+		            << " X: " << (extension() ? "X" : " ")
+		            << " CC: "  << (int) csrcCount()
+		            << " M: " << (marker() ? "M" : " ")
+		            << " PT: " << (int) payloadType()
+		            << " SEQNO: " << seqNumber()
+		            << " TS: " << timestamp();
+	}
 };
 
 struct RTCP_ReportBlock {

src/description.cpp

@@ -106,7 +106,7 @@ Description::Description(const string &sdp, Type type, Role role)
 					               mFingerprint->begin(),
 					               [](char c) { return char(std::toupper(c)); });
 				} else {
-					PLOG_WARNING << "Unknown SDP fingerprint type: " << value;
+					PLOG_WARNING << "Unknown SDP fingerprint format: " << value;
 				}
 			} else if (key == "ice-ufrag") {
 				mIceUfrag = value;

src/icetransport.cpp

@@ -46,11 +46,12 @@ using std::chrono::system_clock;
 
 namespace rtc {
 
-IceTransport::IceTransport(const Configuration &config, Description::Role role,
-                           candidate_callback candidateCallback, state_callback stateChangeCallback,
+IceTransport::IceTransport(const Configuration &config, candidate_callback candidateCallback,
+                           state_callback stateChangeCallback,
                            gathering_state_callback gatheringStateChangeCallback)
-    : Transport(nullptr, std::move(stateChangeCallback)), mRole(role), mMid("0"),
-      mGatheringState(GatheringState::New), mCandidateCallback(std::move(candidateCallback)),
+    : Transport(nullptr, std::move(stateChangeCallback)), mRole(Description::Role::ActPass),
+      mMid("0"), mGatheringState(GatheringState::New),
+      mCandidateCallback(std::move(candidateCallback)),
       mGatheringStateChangeCallback(std::move(gatheringStateChangeCallback)),
       mAgent(nullptr, nullptr) {
 
@@ -139,13 +140,19 @@ Description IceTransport::getLocalDescription(Description::Type type) const {
 	if (juice_get_local_description(mAgent.get(), sdp, JUICE_MAX_SDP_STRING_LEN) < 0)
 		throw std::runtime_error("Failed to generate local SDP");
 
+	// RFC 5763: The endpoint that is the offerer MUST use the setup attribute value of
+	// setup:actpass.
+	// See https://tools.ietf.org/html/rfc5763#section-5
 	return Description(string(sdp), type,
 	                   type == Description::Type::Offer ? Description::Role::ActPass : mRole);
 }
 
 void IceTransport::setRemoteDescription(const Description &description) {
-	mRole = description.role() == Description::Role::Active ? Description::Role::Passive
-	                                                        : Description::Role::Active;
+	if (mRole == Description::Role::ActPass)
+		mRole = description.role() == Description::Role::Active ? Description::Role::Passive
+		                                                        : Description::Role::Active;
+	if (mRole == description.role())
+		throw std::logic_error("Incompatible roles with remote description");
 
 	mMid = description.bundleMid();
 	if (juice_set_remote_description(mAgent.get(),
@@ -316,11 +323,12 @@ void IceTransport::LogCallback(juice_log_level_t level, const char *message) {
 
 namespace rtc {
 
-IceTransport::IceTransport(const Configuration &config, Description::Role role,
-                           candidate_callback candidateCallback, state_callback stateChangeCallback,
+IceTransport::IceTransport(const Configuration &config, candidate_callback candidateCallback,
+                           state_callback stateChangeCallback,
                            gathering_state_callback gatheringStateChangeCallback)
-    : Transport(nullptr, std::move(stateChangeCallback)), mRole(role), mMid("0"),
-      mGatheringState(GatheringState::New), mCandidateCallback(std::move(candidateCallback)),
+    : Transport(nullptr, std::move(stateChangeCallback)), mRole(Description::Role::ActPass),
+      mMid("0"), mGatheringState(GatheringState::New),
+      mCandidateCallback(std::move(candidateCallback)),
       mGatheringStateChangeCallback(std::move(gatheringStateChangeCallback)),
       mNiceAgent(nullptr, nullptr), mMainLoop(nullptr, nullptr) {
 
@@ -526,12 +534,21 @@ Description IceTransport::getLocalDescription(Description::Type type) const {
 
 	std::unique_ptr<gchar[], void (*)(void *)> sdp(nice_agent_generate_local_sdp(mNiceAgent.get()),
 	                                               g_free);
-	return Description(string(sdp.get()), type, mRole);
+
+	// RFC 5763: The endpoint that is the offerer MUST use the setup attribute value of
+	// setup:actpass.
+	// See https://tools.ietf.org/html/rfc5763#section-5
+	return Description(string(sdp.get()), type,
+	                   type == Description::Type::Offer ? Description::Role::ActPass : mRole);
 }
 
 void IceTransport::setRemoteDescription(const Description &description) {
-	mRole = description.role() == Description::Role::Active ? Description::Role::Passive
-	                                                        : Description::Role::Active;
+	if (mRole == Description::Role::ActPass)
+		mRole = description.role() == Description::Role::Active ? Description::Role::Passive
+		                                                        : Description::Role::Active;
+	if (mRole == description.role())
+		throw std::logic_error("Incompatible roles with remote description");
+
 	mMid = description.bundleMid();
 	mTrickleTimeout = !description.ended() ? 30s : 0s;
 

src/icetransport.hpp

@@ -45,8 +45,8 @@ public:
 	using candidate_callback = std::function<void(const Candidate &candidate)>;
 	using gathering_state_callback = std::function<void(GatheringState state)>;
 
-	IceTransport(const Configuration &config, Description::Role role,
-	             candidate_callback candidateCallback, state_callback stateChangeCallback,
+	IceTransport(const Configuration &config, candidate_callback candidateCallback,
+	             state_callback stateChangeCallback,
 	             gathering_state_callback gatheringStateChangeCallback);
 	~IceTransport();
 

src/peerconnection.cpp

@@ -77,7 +77,7 @@ void PeerConnection::close() {
 	mNegotiationNeeded = false;
 
 	// Close data channels asynchronously
-	mProcessor->enqueue(std::bind(&PeerConnection::closeDataChannels, this));
+	mProcessor->enqueue(&PeerConnection::closeDataChannels, this);
 
 	closeTransports();
 }
@@ -187,13 +187,7 @@ void PeerConnection::setLocalDescription(Description::Type type) {
 	}
 	}
 
-	auto iceTransport = std::atomic_load(&mIceTransport);
-	if (!iceTransport) {
-		// RFC 5763: The endpoint that is the offerer MUST use the setup attribute value of
-		// setup:actpass.
-		// See https://tools.ietf.org/html/rfc5763#section-5
-		iceTransport = initIceTransport(Description::Role::ActPass);
-	}
+	auto iceTransport = initIceTransport();
 
 	Description localDescription = iceTransport->getLocalDescription(type);
 	processLocalDescription(std::move(localDescription));
@@ -273,9 +267,7 @@ void PeerConnection::setRemoteDescription(Description description) {
 	auto remoteCandidates = description.extractCandidates();
 	auto type = description.type();
 
-	auto iceTransport = std::atomic_load(&mIceTransport);
-	if (!iceTransport)
-		iceTransport = initIceTransport(Description::Role::ActPass);
+	auto iceTransport = initIceTransport();
 
 	iceTransport->setRemoteDescription(description);
 	processRemoteDescription(std::move(description));
@@ -405,14 +397,14 @@ void PeerConnection::onTrack(std::function<void(std::shared_ptr<Track>)> callbac
 	mTrackCallback = callback;
 }
 
-shared_ptr<IceTransport> PeerConnection::initIceTransport(Description::Role role) {
+shared_ptr<IceTransport> PeerConnection::initIceTransport() {
 	PLOG_VERBOSE << "Starting ICE transport";
 	try {
 		if (auto transport = std::atomic_load(&mIceTransport))
 			return transport;
 
 		auto transport = std::make_shared<IceTransport>(
-		    mConfig, role, weak_bind(&PeerConnection::processLocalCandidate, this, _1),
+		    mConfig, weak_bind(&PeerConnection::processLocalCandidate, this, _1),
 		    [this, weak_this = weak_from_this()](IceTransport::State state) {
 			    auto shared_this = weak_this.lock();
 			    if (!shared_this)
@@ -490,7 +482,7 @@ shared_ptr<DtlsTransport> PeerConnection::initDtlsTransport() {
 				else
 					changeState(State::Connected);
 
-				mProcessor->enqueue(std::bind(&PeerConnection::openTracks, this));
+				mProcessor->enqueue(&PeerConnection::openTracks, this);
 				break;
 			case DtlsTransport::State::Failed:
 				changeState(State::Failed);
@@ -561,16 +553,16 @@ shared_ptr<SctpTransport> PeerConnection::initSctpTransport() {
 			    switch (state) {
 			    case SctpTransport::State::Connected:
 				    changeState(State::Connected);
-				    mProcessor->enqueue(std::bind(&PeerConnection::openDataChannels, this));
+				    mProcessor->enqueue(&PeerConnection::openDataChannels, this);
 				    break;
 			    case SctpTransport::State::Failed:
 				    LOG_WARNING << "SCTP transport failed";
 				    changeState(State::Failed);
-				    mProcessor->enqueue(std::bind(&PeerConnection::remoteCloseDataChannels, this));
+				    mProcessor->enqueue(&PeerConnection::remoteCloseDataChannels, this);
 				    break;
 			    case SctpTransport::State::Disconnected:
 				    changeState(State::Disconnected);
-				    mProcessor->enqueue(std::bind(&PeerConnection::remoteCloseDataChannels, this));
+				    mProcessor->enqueue(&PeerConnection::remoteCloseDataChannels, this);
 				    break;
 			    default:
 				    // Ignore
@@ -1069,19 +1061,17 @@ void PeerConnection::processLocalDescription(Description description) {
 			mCurrentLocalDescription.emplace(std::move(*mLocalDescription));
 		}
 
-		mLocalDescription.emplace(std::move(description));
+		mLocalDescription.emplace(description);
 		mLocalDescription->addCandidates(std::move(existingCandidates));
 	}
 
-	mProcessor->enqueue([this, description = *mLocalDescription]() {
-		PLOG_VERBOSE << "Issuing local description: " << description;
-		mLocalDescriptionCallback(std::move(description));
-	});
+	PLOG_VERBOSE << "Issuing local description: " << description;
+	mProcessor->enqueue(mLocalDescriptionCallback.wrap(), std::move(description));
 
 	// Reciprocated tracks might need to be open
 	if (auto dtlsTransport = std::atomic_load(&mDtlsTransport);
 	    dtlsTransport && dtlsTransport->state() == Transport::State::Connected)
-		mProcessor->enqueue(std::bind(&PeerConnection::openTracks, this));
+		mProcessor->enqueue(&PeerConnection::openTracks, this);
 }
 
 void PeerConnection::processLocalCandidate(Candidate candidate) {
@@ -1092,10 +1082,8 @@ void PeerConnection::processLocalCandidate(Candidate candidate) {
 	candidate.resolve(Candidate::ResolveMode::Simple); // for proper SDP generation later
 	mLocalDescription->addCandidate(candidate);
 
-	mProcessor->enqueue([this, candidate = std::move(candidate)]() {
-		PLOG_VERBOSE << "Issuing local candidate: " << candidate;
-		mLocalCandidateCallback(std::move(candidate));
-	});
+	PLOG_VERBOSE << "Issuing local candidate: " << candidate;
+	mProcessor->enqueue(mLocalCandidateCallback.wrap(), std::move(candidate));
 }
 
 void PeerConnection::processRemoteDescription(Description description) {
@@ -1150,12 +1138,11 @@ void PeerConnection::triggerDataChannel(weak_ptr<DataChannel> weakDataChannel) {
 	if (!dataChannel)
 		return;
 
-	mProcessor->enqueue(
-	    [this, dataChannel = std::move(dataChannel)]() { mDataChannelCallback(dataChannel); });
+	mProcessor->enqueue(mDataChannelCallback.wrap(), std::move(dataChannel));
 }
 
 void PeerConnection::triggerTrack(std::shared_ptr<Track> track) {
-	mProcessor->enqueue([this, track = std::move(track)]() { mTrackCallback(track); });
+	mProcessor->enqueue(mTrackCallback.wrap(), std::move(track));
 }
 
 bool PeerConnection::changeState(State state) {
@@ -1177,7 +1164,7 @@ bool PeerConnection::changeState(State state) {
 		// This is the last state change, so we may steal the callback
 		mProcessor->enqueue([cb = std::move(mStateChangeCallback)]() { cb(State::Closed); });
 	else
-		mProcessor->enqueue([this, state]() { mStateChangeCallback(state); });
+		mProcessor->enqueue(mStateChangeCallback.wrap(), state);
 
 	return true;
 }
@@ -1189,7 +1176,7 @@ bool PeerConnection::changeGatheringState(GatheringState state) {
 	std::ostringstream s;
 	s << state;
 	PLOG_INFO << "Changed gathering state to " << s.str();
-	mProcessor->enqueue([this, state] { mGatheringStateChangeCallback(state); });
+	mProcessor->enqueue(mGatheringStateChangeCallback.wrap(), state);
 	return true;
 }
 
@@ -1200,7 +1187,7 @@ bool PeerConnection::changeSignalingState(SignalingState state) {
 	std::ostringstream s;
 	s << state;
 	PLOG_INFO << "Changed signaling state to " << s.str();
-	mProcessor->enqueue([this, state] { mSignalingStateChangeCallback(state); });
+	mProcessor->enqueue(mSignalingStateChangeCallback.wrap(), state);
 	return true;
 }
 

src/processor.cpp

@@ -20,6 +20,8 @@
 
 namespace rtc {
 
+Processor::Processor(size_t limit) : mTasks(limit) {}
+
 Processor::~Processor() { join(); }
 
 void Processor::join() {
@@ -29,15 +31,13 @@ void Processor::join() {
 
 void Processor::schedule() {
 	std::unique_lock lock(mMutex);
-	if (mTasks.empty()) {
+	if (auto next = mTasks.tryPop()) {
+		ThreadPool::Instance().enqueue(std::move(*next));
+	} else {
 		// No more tasks
 		mPending = false;
 		mCondition.notify_all();
-		return;
 	}
-
-	ThreadPool::Instance().enqueue(std::move(mTasks.front()));
-	mTasks.pop();
 }
 
 } // namespace rtc

src/processor.hpp

@@ -22,6 +22,7 @@
 #include "include.hpp"
 #include "init.hpp"
 #include "threadpool.hpp"
+#include "queue.hpp"
 
 #include <condition_variable>
 #include <future>
@@ -34,7 +35,7 @@ namespace rtc {
 // Processed tasks in order by delegating them to the thread pool
 class Processor final {
 public:
-	Processor() = default;
+	Processor(size_t limit = 0);
 	~Processor();
 
 	Processor(const Processor &) = delete;
@@ -52,7 +53,7 @@ protected:
 	// Keep an init token
 	const init_token mInitToken = Init::Token();
 
-	std::queue<std::function<void()>> mTasks;
+	Queue<std::function<void()>> mTasks;
 	bool mPending = false; // true iff a task is pending in the thread pool
 
 	mutable std::mutex mMutex;
@@ -71,7 +72,7 @@ template <class F, class... Args> void Processor::enqueue(F &&f, Args &&... args
 		ThreadPool::Instance().enqueue(std::move(task));
 		mPending = true;
 	} else {
-		mTasks.emplace(std::move(task));
+		mTasks.push(std::move(task));
 	}
 }
 

src/sctptransport.cpp

@@ -100,11 +100,12 @@ SctpTransport::SctpTransport(std::shared_ptr<Transport> lower, uint16_t port,
 		Instances.insert(this);
 	}
 
-	mSock = usrsctp_socket(AF_CONN, SOCK_STREAM, IPPROTO_SCTP, &SctpTransport::RecvCallback,
-	                       &SctpTransport::SendCallback, 0, this);
+	mSock = usrsctp_socket(AF_CONN, SOCK_STREAM, IPPROTO_SCTP, nullptr, nullptr, 0, nullptr);
 	if (!mSock)
 		throw std::runtime_error("Could not create SCTP socket, errno=" + std::to_string(errno));
 
+	usrsctp_set_upcall(mSock, &SctpTransport::UpcallCallback, this);
+
 	if (usrsctp_set_non_blocking(mSock, 1))
 		throw std::runtime_error("Unable to set non-blocking mode, errno=" + std::to_string(errno));
 
@@ -122,6 +123,10 @@ SctpTransport::SctpTransport(std::shared_ptr<Transport> lower, uint16_t port,
 	if (usrsctp_setsockopt(mSock, IPPROTO_SCTP, SCTP_ENABLE_STREAM_RESET, &av, sizeof(av)))
 		throw std::runtime_error("Could not set socket option SCTP_ENABLE_STREAM_RESET, errno=" +
 		                         std::to_string(errno));
+	int on = 1;
+	if (usrsctp_setsockopt(mSock, IPPROTO_SCTP, SCTP_RECVRCVINFO, &on, sizeof(on)))
+		throw std::runtime_error("Could set socket option SCTP_RECVRCVINFO, errno=" +
+		                         std::to_string(errno));
 
 	struct sctp_event se = {};
 	se.se_assoc_id = SCTP_ALL_ASSOC;
@@ -225,6 +230,7 @@ bool SctpTransport::stop() {
 
 void SctpTransport::close() {
 	if (mSock) {
+		mProcessor.join();
 		usrsctp_close(mSock);
 		mSock = nullptr;
 	}
@@ -319,6 +325,59 @@ void SctpTransport::incoming(message_ptr message) {
 	usrsctp_conninput(this, message->data(), message->size(), 0);
 }
 
+void SctpTransport::doRecv() {
+	std::lock_guard lock(mRecvMutex);
+	try {
+		while (true) {
+			const size_t bufferSize = 65536;
+			byte buffer[bufferSize];
+			socklen_t fromlen = 0;
+			struct sctp_rcvinfo info = {};
+			socklen_t infolen = sizeof(info);
+			unsigned int infotype = 0;
+			int flags = 0;
+			ssize_t len = usrsctp_recvv(mSock, buffer, bufferSize, nullptr, &fromlen, &info,
+			                            &infolen, &infotype, &flags);
+			if (len < 0) {
+				if (errno == EWOULDBLOCK || errno == EAGAIN || errno == ECONNRESET)
+					break;
+				else
+					throw std::runtime_error("SCTP recv failed, errno=" + std::to_string(errno));
+			}
+
+			PLOG_VERBOSE << "SCTP recv, len=" << len;
+
+			// SCTP_FRAGMENT_INTERLEAVE does not seem to work as expected for messages > 64KB,
+			// therefore partial notifications and messages need to be handled separately.
+			if (flags & MSG_NOTIFICATION) {
+				// SCTP event notification
+				mPartialNotification.insert(mPartialNotification.end(), buffer, buffer + len);
+				if (flags & MSG_EOR) {
+					// Notification is complete, process it
+					auto notification =
+					    reinterpret_cast<union sctp_notification *>(mPartialNotification.data());
+					processNotification(notification, mPartialNotification.size());
+					mPartialNotification.clear();
+				}
+			} else {
+				// SCTP message
+				mPartialMessage.insert(mPartialMessage.end(), buffer, buffer + len);
+				if (flags & MSG_EOR) {
+					// Message is complete, process it
+					if (infotype != SCTP_RECVV_RCVINFO)
+						throw std::runtime_error("Missing SCTP recv info");
+
+					processData(std::move(mPartialMessage), info.rcv_sid,
+					            PayloadId(ntohl(info.rcv_ppid)));
+					mPartialMessage.clear();
+				}
+			}
+		}
+	} catch (const std::exception &e) {
+		PLOG_WARNING << e.what();
+	}
+}
+
 bool SctpTransport::trySendQueue() {
 	// Requires mSendMutex to be locked
 	while (auto next = mSendQueue.peek()) {
@@ -472,44 +531,19 @@ bool SctpTransport::safeFlush() {
 	}
 }
 
-int SctpTransport::handleRecv(struct socket * /*sock*/, union sctp_sockstore /*addr*/,
-                              const byte *data, size_t len, struct sctp_rcvinfo info, int flags) {
-	try {
-		PLOG_VERBOSE << "Handle recv, len=" << len;
+void SctpTransport::handleUpcall() {
+	if(!mSock)
+		return;
 
-		// SCTP_FRAGMENT_INTERLEAVE does not seem to work as expected for messages > 64KB,
-		// therefore partial notifications and messages need to be handled separately.
-		if (flags & MSG_NOTIFICATION) {
-			// SCTP event notification
-			mPartialNotification.insert(mPartialNotification.end(), data, data + len);
-			if (flags & MSG_EOR) {
-				// Notification is complete, process it
-				processNotification(
-				    reinterpret_cast<const union sctp_notification *>(mPartialNotification.data()),
-				    mPartialNotification.size());
-				mPartialNotification.clear();
-			}
-		} else {
-			// SCTP message
-			mPartialMessage.insert(mPartialMessage.end(), data, data + len);
-			if (flags & MSG_EOR) {
-				// Message is complete, process it
-				processData(std::move(mPartialMessage), info.rcv_sid,
-				            PayloadId(ntohl(info.rcv_ppid)));
-				mPartialMessage.clear();
-			}
-		}
+	PLOG_VERBOSE << "Handle upcall";
 
-	} catch (const std::exception &e) {
-		PLOG_ERROR << "SCTP recv: " << e.what();
-		return -1;
-	}
-	return 0; // success
-}
+	int events = usrsctp_get_events(mSock);
 
-int SctpTransport::handleSend(size_t free) {
-	PLOG_VERBOSE << "Handle send, free=" << free;
-	return safeFlush() ? 0 : -1;
+	if (events & SCTP_EVENT_READ)
+		mProcessor.enqueue(&SctpTransport::doRecv, this);
+
+	if (events & SCTP_EVENT_WRITE)
+		mProcessor.enqueue(&SctpTransport::safeFlush, this);
 }
 
 int SctpTransport::handleWrite(byte *data, size_t len, uint8_t /*tos*/, uint8_t /*set_df*/) {
@@ -699,31 +733,14 @@ std::optional<milliseconds> SctpTransport::rtt() {
 	return milliseconds(status.sstat_primary.spinfo_srtt);
 }
 
-int SctpTransport::RecvCallback(struct socket *sock, union sctp_sockstore addr, void *data,
-                                size_t len, struct sctp_rcvinfo recv_info, int flags,
-                                void *ulp_info) {
-	auto *transport = static_cast<SctpTransport *>(ulp_info);
-
-	std::shared_lock lock(InstancesMutex);
-	if (Instances.find(transport) == Instances.end()) {
-		free(data);
-		return -1;
-	}
-
-	int ret =
-	    transport->handleRecv(sock, addr, static_cast<const byte *>(data), len, recv_info, flags);
-	free(data);
-	return ret;
-}
-
-int SctpTransport::SendCallback(struct socket *, uint32_t sb_free, void *ulp_info) {
-	auto *transport = static_cast<SctpTransport *>(ulp_info);
+void SctpTransport::UpcallCallback(struct socket *, void *arg, int /* flags */) {
+	auto *transport = static_cast<SctpTransport *>(arg);
 
 	std::shared_lock lock(InstancesMutex);
 	if (Instances.find(transport) == Instances.end())
-		return -1;
+		return;
 
-	return transport->handleSend(size_t(sb_free));
+	transport->handleUpcall();
 }
 
 int SctpTransport::WriteCallback(void *ptr, void *data, size_t len, uint8_t tos, uint8_t set_df) {

src/sctptransport.hpp

@@ -21,8 +21,10 @@
 
 #include "include.hpp"
 #include "peerconnection.hpp"
+#include "processor.hpp"
 #include "queue.hpp"
 #include "transport.hpp"
+#include "processor.hpp"
 
 #include <condition_variable>
 #include <functional>
@@ -35,7 +37,7 @@
 
 namespace rtc {
 
-class SctpTransport : public Transport {
+class SctpTransport final : public Transport {
 public:
 	static void Init();
 	static void Cleanup();
@@ -76,15 +78,14 @@ private:
 	void close();
 	void incoming(message_ptr message) override;
 
+	void doRecv();
 	bool trySendQueue();
 	bool trySendMessage(message_ptr message);
 	void updateBufferedAmount(uint16_t streamId, long delta);
 	void sendReset(uint16_t streamId);
 	bool safeFlush();
 
-	int handleRecv(struct socket *sock, union sctp_sockstore addr, const byte *data, size_t len,
-	               struct sctp_rcvinfo recv_info, int flags);
-	int handleSend(size_t free);
+	void handleUpcall();
 	int handleWrite(byte *data, size_t len, uint8_t tos, uint8_t set_df);
 
 	void processData(binary &&data, uint16_t streamId, PayloadId ppid);
@@ -93,7 +94,8 @@ private:
 	const uint16_t mPort;
 	struct socket *mSock;
 
-	std::mutex mSendMutex;
+	Processor mProcessor;
+	std::mutex mRecvMutex, mSendMutex;
 	Queue<message_ptr> mSendQueue;
 	std::map<uint16_t, size_t> mBufferedAmount;
 	amount_callback mBufferedAmountCallback;
@@ -109,9 +111,7 @@ private:
 	// Stats
 	std::atomic<size_t> mBytesSent = 0, mBytesReceived = 0;
 
-	static int RecvCallback(struct socket *sock, union sctp_sockstore addr, void *data, size_t len,
-	                        struct sctp_rcvinfo recv_info, int flags, void *ulp_info);
-	static int SendCallback(struct socket *sock, uint32_t sb_free, void *ulp_info);
+	static void UpcallCallback(struct socket *sock, void *arg, int flags);
 	static int WriteCallback(void *sctp_ptr, void *data, size_t len, uint8_t tos, uint8_t set_df);
 
 	static std::unordered_set<SctpTransport *> Instances;